SPERT: A STATELESS PROTOCOL FOR ENERGY-SENSITIVE REAL-TIME ROUTING FOR WIRELESS SENSOR NETWORK Sohail Jabbar, Abid Ali Minhas, Raja Adeel Akhtar Abstract— Putting constraints on performance of a system in the temporal domain, some times turns right into wrong and update into outdate. These are the scenarios where apposite value of time inveterate in the reality. But such timing precision not only requires tightly scheduled performance constraints but also requires optimal design and operation of all system components. Any malfunctioning at any relevant aspect may causes a serious disaster and even loss of human lives. Managing and interacting with such real-time system becomes much intricate when the resources are limited as in wireless sensor nodes. A wireless sensor node is typically comprises of sensing unit, processing unit and transmission unit. Intercommunication of these energy, memory and processing constraint devices form wireless sensor network. In this paper, SPERT: a mechanism of approaching the sink from multi-sources in the fast and ef?cient manner, is proposed. It simply relies on in-network processed information which appreciatory decreases too much beacons among neighbor- ing nodes resulting in increasing the network lifetime. More-over, every node is aware of its time to get its message to destination. Thus delay in processing and decision making also decreases leading in favor to real-time communication. I. I NTRODUCTION WSN is cooperative[1] network of low cost, self-organized, self-configured, short lived, less computational power and less memory containing nodes. Each node consists of processing capability (one or more microcontroller, CPUs or DSP chips), may contain multiple types of memory (Flash, data or program memory), have an RF Transceiver (usually with single omni directional antenna), have a power source (energy storage or energy scavenging cells) and accommodates various sensors and actuators[2]. This network can be connected to the IP-based network through some gateway as shown in Figure 1[3]. With the passage of time, relentless progress in hardware as well as software based technologies make it feasible to indulge sensors in various components of environment. This emerging technology has its application in wildlife monitoring[4], cold chain monitoring[5], Glacier monitoring[6], rescue of avalanche victims[7], cattle herding, vital sign monitoring[8], ocean water and bed monitoring, tracking vehicles, sniper localization[9], volcano monitoring and tunnel monitoring and rescue. Underwater sensor network that are typically based on ultrasound, is also a key application of WSN[10][11]. S. Jabbar, A. A. Minhas, R. A. Akhtar are with Bharia University, Islamabad, Pakistan. Email (sjabbar, abid,, rajaadeel)research@gmail.com. Fig. 1. Components of a sensor node Ad hoc network inherited some of the tribulations of wireless communication networks like Lossy links, unreliable time in-varying and asymmetric channel, hidden node and exposed node, improperly defined coverage boundary etc. Ad hoc network puts a messy contribution in this knotted portfolio in the form of multi hop environment, location- awareness, node mobility, dynamically changing topology, vulnerability of channel and nodes and different aspects in QoS. Specifically in WSN, in addition to most of the aforementioned issues, network partitioning, localization, calibration, data fusion, aggregation and dissemination, coverage issues, self organizing and self administration, scalability, load balancing, node clustering, topology management, end-to-end delay constraint routing, security and privacy, heterogeneity, and other energy, memory, power and bandwidth constraints are the active challenges. In the closer view, node scheduling, hole problem, avoiding and coping with void node areas, node failure and QoS relating factors are under great concentration of researchers where QoS is a level of service in achieving the target with sufficient resources by fulfilling the requested QoS parameters. End- 978-1-4244-4609-4/09/$25.00 ©2009 IEEE Authorized licensed use limited to: Bahria University. Downloaded on February 17,2010 at 06:47:47 EST from IEEE Xplore. Restrictions apply.